Dresden 2026 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 3: Correlated Electrons: Electronic Structure Calculations
TT 3.2: Vortrag
Montag, 9. März 2026, 09:45–10:00, HSZ/0103
Imaging the 3d orbitals in V2O3 across the AFI-PM-PI transitions — •Paulius Dolmantas1, Chun-Fu Chang1, Martin Sundermann1,2, Hlynur Gretarsson2, Jonathan Denlinger3, Maurits Haverkort4, and Liu Hao Tjeng1 — 1Max Planck Institute for Chemical Physics of Solids, Dresden, Germany — 2DESY, Hamburg, Germany — 3ALS, Berkeley, USA — 4Institute for Theoretical Physics, Heidelberg University, Heidelberg, Germany
V2O3 exhibits a rich phase diagram in which the transitions between the antiferromagnetic insulating (AFI), paramagnetic metallic (PM) and paramagnetic insulating (PI) phases are all 1st order. The presence of c-axis V-V dimers in the crystal structure is the reason for proposing the standard model for V2O3 in which a1g-a1g molecular singlets are formed, leaving each V ion with an S=1/2 electron to generate the complex phase diagram. Numerous ab-initio electronic structure calculations and spectroscopy studies have been carried out to determine the mechanism of the phase transitions, with contradicting results. The main problem underlying this issue is that the actual valence charge density in V2O3 has not yet been determined with sufficient reliability, a quantity that forms the very basis for modeling the properties. Here we utilized a newly developed experimental method with which we can make a direct image of the active orbital. The method is non-resonant inelastic X-ray scattering using an s-core level. Our experimental results unveiled that the a1g-a1g molecular singlets have not materialized and that instead, subtle changes changes in the orbital occupations across the transitions must be considered.
Keywords: Complex Oxides; V2O3; Orbital imaging; Phase transitions